This EC is an incompatible variant of the typical Chrome OS embedded
controller.  It uses the same low-level communication and a similar
protocol with some significant differences.  The EC firmware does
not support the same mailbox commands so it is not registered as a
cros_ec device type.  This commit exports the wilco_ec_mailbox()
function so that other modules can use it to communicate with the EC.

Signed-off-by: Duncan Laurie <dlau...@google.com>
Signed-off-by: Nick Crews <ncr...@chromium.org>
---

Changes in v8: None
Changes in v7: None
Changes in v6:
- Re-added WILCO_EC_FLAG_EXTENDED_DATA and went back to always
  reading either EC_MAILBOX_DATA_SIZE or EC_MAILBOX_DATA_SIZE_EXTENDED
  bytes, since it turns out the EC always expects you to calculate the
  checksum over all of them.
- Split WILCO_EC_MSG_TELEMETRY into WILCO_EC_MSG_TELEMETRY_SHORT and
  WILCO_EC_MSG_TELEMETRY_LONG, since there will be two different
  commands.
- A couple comment and err message polishes

Changes in v5:
- move checking of NO_RESPONSE flag before timeout check,
  so now timeout doesn't always happen when EC isn't supposed
  to respond.
- rm WILCO_EC_FLAG_EXTENDED_DATA, that is already obvious from
  wilco_ec_message.response_size

Changes in v4:
- add #define DRV_NAME
- remove redundant Kconfig nesting
- changed my email to @chromium.org
- Add better explanation of what core.c does

Changes in v3:
- remove unused ret in probe()
- Add newline spacer in probe()
- rm unnecessary res in get_resource()
- s/8bit/8-bit
- rm first sleep when sending command to EC

Changes in v2:
- Remove COMPILE_TEST from Kconfig because inb()/outb()
won't work on anything but X86
- Add myself as module author
- Tweak mailbox()

 drivers/platform/chrome/Kconfig            |   4 +-
 drivers/platform/chrome/Makefile           |   2 +
 drivers/platform/chrome/wilco_ec/Kconfig   |  11 +
 drivers/platform/chrome/wilco_ec/Makefile  |   4 +
 drivers/platform/chrome/wilco_ec/core.c    | 104 +++++++++
 drivers/platform/chrome/wilco_ec/mailbox.c | 236 +++++++++++++++++++++
 include/linux/platform_data/wilco-ec.h     | 140 ++++++++++++
 7 files changed, 500 insertions(+), 1 deletion(-)
 create mode 100644 drivers/platform/chrome/wilco_ec/Kconfig
 create mode 100644 drivers/platform/chrome/wilco_ec/Makefile
 create mode 100644 drivers/platform/chrome/wilco_ec/core.c
 create mode 100644 drivers/platform/chrome/wilco_ec/mailbox.c
 create mode 100644 include/linux/platform_data/wilco-ec.h

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 16b1615958aa..bf889adfd4ef 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -49,6 +49,8 @@ config CHROMEOS_TBMC
          To compile this driver as a module, choose M here: the
          module will be called chromeos_tbmc.
 
+source "drivers/platform/chrome/wilco_ec/Kconfig"
+
 config CROS_EC_CTL
         tristate
 
@@ -86,7 +88,7 @@ config CROS_EC_LPC
 
 config CROS_EC_LPC_MEC
        bool "ChromeOS Embedded Controller LPC Microchip EC (MEC) variant"
-       depends on CROS_EC_LPC
+       depends on CROS_EC_LPC || WILCO_EC
        default n
        help
          If you say Y here, a variant LPC protocol for the Microchip EC
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index cd591bf872bb..7242ee2b13c5 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -13,3 +13,5 @@ cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)        += 
cros_ec_lpc_mec.o
 obj-$(CONFIG_CROS_EC_LPC)              += cros_ec_lpcs.o
 obj-$(CONFIG_CROS_EC_PROTO)            += cros_ec_proto.o
 obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)   += cros_kbd_led_backlight.o
+
+obj-$(CONFIG_WILCO_EC)                 += wilco_ec/
diff --git a/drivers/platform/chrome/wilco_ec/Kconfig 
b/drivers/platform/chrome/wilco_ec/Kconfig
new file mode 100644
index 000000000000..20945a301ec6
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/Kconfig
@@ -0,0 +1,11 @@
+config WILCO_EC
+       tristate "ChromeOS Wilco Embedded Controller"
+       depends on ACPI && X86
+       select CROS_EC_LPC_MEC
+       help
+         If you say Y here, you get support for talking to the ChromeOS
+         Wilco EC over an eSPI bus. This uses a simple byte-level protocol
+         with a checksum.
+
+         To compile this driver as a module, choose M here: the
+         module will be called wilco_ec.
diff --git a/drivers/platform/chrome/wilco_ec/Makefile 
b/drivers/platform/chrome/wilco_ec/Makefile
new file mode 100644
index 000000000000..03b32301dc61
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+
+wilco_ec-objs                          := core.o mailbox.o
+obj-$(CONFIG_WILCO_EC)                 += wilco_ec.o
diff --git a/drivers/platform/chrome/wilco_ec/core.c 
b/drivers/platform/chrome/wilco_ec/core.c
new file mode 100644
index 000000000000..20ecc580d108
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/core.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Core driver for Wilco Embedded Controller
+ *
+ * Copyright 2018 Google LLC
+ *
+ * This is the entry point for the drivers that control the Wilco EC.
+ * This driver is responsible for several tasks:
+ * - Initialize the register interface that is used by wilco_ec_mailbox()
+ * - Create a platform device which is picked up by the debugfs driver
+ * - Create a platform device which is picked up by the RTC driver
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/platform_data/wilco-ec.h>
+#include <linux/platform_device.h>
+
+#include "../cros_ec_lpc_mec.h"
+
+#define DRV_NAME "wilco-ec"
+
+static struct resource *wilco_get_resource(struct platform_device *pdev,
+                                          int index)
+{
+       struct device *dev = &pdev->dev;
+       struct resource *res;
+
+       res = platform_get_resource(pdev, IORESOURCE_IO, index);
+       if (!res) {
+               dev_dbg(dev, "Couldn't find IO resource %d\n", index);
+               return res;
+       }
+
+       return devm_request_region(dev, res->start, resource_size(res),
+                                  dev_name(dev));
+}
+
+static int wilco_ec_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct wilco_ec_device *ec;
+
+       ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
+       if (!ec)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, ec);
+       ec->dev = dev;
+       mutex_init(&ec->mailbox_lock);
+
+       /* Largest data buffer size requirement is extended data response */
+       ec->data_size = sizeof(struct wilco_ec_response) +
+               EC_MAILBOX_DATA_SIZE_EXTENDED;
+       ec->data_buffer = devm_kzalloc(dev, ec->data_size, GFP_KERNEL);
+       if (!ec->data_buffer)
+               return -ENOMEM;
+
+       /* Prepare access to IO regions provided by ACPI */
+       ec->io_data = wilco_get_resource(pdev, 0);      /* Host Data */
+       ec->io_command = wilco_get_resource(pdev, 1);   /* Host Command */
+       ec->io_packet = wilco_get_resource(pdev, 2);    /* MEC EMI */
+       if (!ec->io_data || !ec->io_command || !ec->io_packet)
+               return -ENODEV;
+
+       /* Initialize cros_ec register interface for communication */
+       cros_ec_lpc_mec_init(ec->io_packet->start,
+                            ec->io_packet->start + EC_MAILBOX_DATA_SIZE);
+
+       return 0;
+}
+
+static int wilco_ec_remove(struct platform_device *pdev)
+{
+       /* Teardown cros_ec interface */
+       cros_ec_lpc_mec_destroy();
+
+       return 0;
+}
+
+static const struct acpi_device_id wilco_ec_acpi_device_ids[] = {
+       { "GOOG000C", 0 },
+       { }
+};
+MODULE_DEVICE_TABLE(acpi, wilco_ec_acpi_device_ids);
+
+static struct platform_driver wilco_ec_driver = {
+       .driver = {
+               .name = DRV_NAME,
+               .acpi_match_table = wilco_ec_acpi_device_ids,
+       },
+       .probe = wilco_ec_probe,
+       .remove = wilco_ec_remove,
+};
+
+module_platform_driver(wilco_ec_driver);
+
+MODULE_AUTHOR("Nick Crews <ncr...@chromium.org>");
+MODULE_AUTHOR("Duncan Laurie <dlau...@chromium.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChromeOS Wilco Embedded Controller driver");
+MODULE_ALIAS("platform:" DRV_NAME);
diff --git a/drivers/platform/chrome/wilco_ec/mailbox.c 
b/drivers/platform/chrome/wilco_ec/mailbox.c
new file mode 100644
index 000000000000..c7028488e575
--- /dev/null
+++ b/drivers/platform/chrome/wilco_ec/mailbox.c
@@ -0,0 +1,236 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mailbox interface for Wilco Embedded Controller
+ *
+ * Copyright 2018 Google LLC
+ *
+ * The Wilco EC is similar to a typical ChromeOS embedded controller.
+ * It uses the same MEC based low-level communication and a similar
+ * protocol, but with some important differences.  The EC firmware does
+ * not support the same mailbox commands so it is not registered as a
+ * cros_ec device type.
+ *
+ * Most messages follow a standard format, but there are some exceptions
+ * and an interface is provided to do direct/raw transactions that do not
+ * make assumptions about byte placement.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/platform_data/wilco-ec.h>
+#include <linux/platform_device.h>
+
+#include "../cros_ec_lpc_mec.h"
+
+/* Version of mailbox interface */
+#define EC_MAILBOX_VERSION             0
+
+/* Command to start mailbox transaction */
+#define EC_MAILBOX_START_COMMAND       0xda
+
+/* Version of EC protocol */
+#define EC_MAILBOX_PROTO_VERSION       3
+
+/* Number of header bytes to be counted as data bytes */
+#define EC_MAILBOX_DATA_EXTRA          2
+
+/* Maximum timeout */
+#define EC_MAILBOX_TIMEOUT             HZ
+
+/* EC response flags */
+#define EC_CMDR_DATA           BIT(0)  /* Data ready for host to read */
+#define EC_CMDR_PENDING                BIT(1)  /* Write pending to EC */
+#define EC_CMDR_BUSY           BIT(2)  /* EC is busy processing a command */
+#define EC_CMDR_CMD            BIT(3)  /* Last host write was a command */
+
+/**
+ * wilco_ec_response_timed_out() - Wait for EC response.
+ * @ec: EC device.
+ *
+ * Return: true if EC timed out, false if EC did not time out.
+ */
+static bool wilco_ec_response_timed_out(struct wilco_ec_device *ec)
+{
+       unsigned long timeout = jiffies + EC_MAILBOX_TIMEOUT;
+
+       do {
+               if (!(inb(ec->io_command->start) &
+                     (EC_CMDR_PENDING | EC_CMDR_BUSY)))
+                       return false;
+               usleep_range(100, 200);
+       } while (time_before(jiffies, timeout));
+
+       return true;
+}
+
+/**
+ * wilco_ec_checksum() - Compute 8-bit checksum over data range.
+ * @data: Data to checksum.
+ * @size: Number of bytes to checksum.
+ *
+ * Return: 8-bit checksum of provided data.
+ */
+static u8 wilco_ec_checksum(const void *data, size_t size)
+{
+       u8 *data_bytes = (u8 *)data;
+       u8 checksum = 0;
+       size_t i;
+
+       for (i = 0; i < size; i++)
+               checksum += data_bytes[i];
+
+       return checksum;
+}
+
+/**
+ * wilco_ec_prepare() - Prepare the request structure for the EC.
+ * @msg: EC message with request information.
+ * @rq: EC request structure to fill.
+ */
+static void wilco_ec_prepare(struct wilco_ec_message *msg,
+                            struct wilco_ec_request *rq)
+{
+       memset(rq, 0, sizeof(*rq));
+
+       /* Handle messages without trimming bytes from the request */
+       if (msg->request_size && msg->flags & WILCO_EC_FLAG_RAW_REQUEST) {
+               rq->reserved_raw = *(u8 *)msg->request_data;
+               msg->request_size--;
+               memmove(msg->request_data, msg->request_data + 1,
+                       msg->request_size);
+       }
+
+       /* Fill in request packet */
+       rq->struct_version = EC_MAILBOX_PROTO_VERSION;
+       rq->mailbox_id = msg->type;
+       rq->mailbox_version = EC_MAILBOX_VERSION;
+       rq->data_size = msg->request_size + EC_MAILBOX_DATA_EXTRA;
+       rq->command = msg->command;
+
+       /* Checksum header and data */
+       rq->checksum = wilco_ec_checksum(rq, sizeof(*rq));
+       rq->checksum += wilco_ec_checksum(msg->request_data, msg->request_size);
+       rq->checksum = -rq->checksum;
+}
+
+/**
+ * wilco_ec_transfer() - Perform actual data transfer.
+ * @ec: EC device.
+ * @msg: EC message data for request and response.
+ * @rq: Filled in request structure
+ *
+ * Context: ec->mailbox_lock should be held while using this function.
+ * Return: number of bytes received or negative error code on failure.
+ */
+int wilco_ec_transfer(struct wilco_ec_device *ec, struct wilco_ec_message *msg,
+                     struct wilco_ec_request *rq)
+{
+       struct wilco_ec_response *rs;
+       u8 checksum;
+       u8 flag;
+       size_t size;
+
+       /* Write request header, then data */
+       cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, 0, sizeof(*rq), (u8 *)rq);
+       cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, sizeof(*rq), msg->request_size,
+                                msg->request_data);
+
+       /* Start the command */
+       outb(EC_MAILBOX_START_COMMAND, ec->io_command->start);
+
+       /* For some commands (eg shutdown) the EC will not respond, that's OK */
+       if (msg->flags & WILCO_EC_FLAG_NO_RESPONSE) {
+               dev_dbg(ec->dev, "EC does not respond to this command\n");
+               return 0;
+       }
+
+       /* Wait for it to complete */
+       if (wilco_ec_response_timed_out(ec)) {
+               dev_dbg(ec->dev, "response timed out\n");
+               return -ETIMEDOUT;
+       }
+
+       /* Check result */
+       flag = inb(ec->io_data->start);
+       if (flag) {
+               dev_dbg(ec->dev, "bad response: 0x%02x\n", flag);
+               return -EIO;
+       }
+
+       if (msg->flags & WILCO_EC_FLAG_EXTENDED_DATA)
+               size = EC_MAILBOX_DATA_SIZE_EXTENDED;
+       else
+               size = EC_MAILBOX_DATA_SIZE;
+
+       /* Read back response */
+       rs = ec->data_buffer;
+       checksum = cros_ec_lpc_io_bytes_mec(MEC_IO_READ, 0,
+                                           sizeof(*rs) + size, (u8 *)rs);
+       if (checksum) {
+               dev_dbg(ec->dev, "bad packet checksum 0x%02x\n", rs->checksum);
+               return -EBADMSG;
+       }
+
+       /* Check that the EC reported success */
+       msg->result = rs->result;
+       if (msg->result) {
+               dev_dbg(ec->dev, "bad response: 0x%02x\n", msg->result);
+               return -EBADMSG;
+       }
+
+       /* Check the returned data size, skipping the header */
+       if (rs->data_size != size) {
+               dev_dbg(ec->dev, "unexpected packet size (%u != %zu)",
+                       rs->data_size, size);
+               return -EMSGSIZE;
+       }
+
+       /* Skip 1 response data byte unless specified */
+       size = (msg->flags & WILCO_EC_FLAG_RAW_RESPONSE) ? 0 : 1;
+       if ((ssize_t) rs->data_size - size < msg->response_size) {
+               dev_dbg(ec->dev, "response data too short (%zd < %zu)",
+                       (ssize_t) rs->data_size - size, msg->response_size);
+               return -EMSGSIZE;
+       }
+
+       /* Ignore response data bytes as requested */
+       memcpy(msg->response_data, rs->data + size, msg->response_size);
+
+       /* Return actual amount of data received */
+       return msg->response_size;
+}
+
+/**
+ * wilco_ec_mailbox() - Send EC request and receive EC response.
+ * @ec: EC device.
+ * @msg: EC message data for request and response.
+ *
+ * On entry msg->type, msg->flags, msg->command, msg->request_size,
+ * msg->response_size, and msg->request_data should all be filled in.
+ *
+ * On exit msg->result and msg->response_data will be filled.
+ *
+ * Return: number of bytes received or negative error code on failure.
+ */
+int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg)
+{
+       struct wilco_ec_request *rq;
+       int ret;
+
+       dev_dbg(ec->dev, "cmd=%02x type=%04x flags=%02x rslen=%zu rqlen=%zu\n",
+               msg->command, msg->type, msg->flags, msg->response_size,
+               msg->request_size);
+
+       /* Prepare request packet */
+       rq = ec->data_buffer;
+       wilco_ec_prepare(msg, rq);
+
+       mutex_lock(&ec->mailbox_lock);
+       ret = wilco_ec_transfer(ec, msg, rq);
+       mutex_unlock(&ec->mailbox_lock);
+
+       return ret;
+
+}
+EXPORT_SYMBOL_GPL(wilco_ec_mailbox);
diff --git a/include/linux/platform_data/wilco-ec.h 
b/include/linux/platform_data/wilco-ec.h
new file mode 100644
index 000000000000..0feb4b520a54
--- /dev/null
+++ b/include/linux/platform_data/wilco-ec.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ChromeOS Wilco Embedded Controller
+ *
+ * Copyright 2018 Google LLC
+ */
+
+#ifndef WILCO_EC_H
+#define WILCO_EC_H
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+
+/* Message flags for using the mailbox() interface */
+#define WILCO_EC_FLAG_NO_RESPONSE      BIT(0) /* EC does not respond */
+#define WILCO_EC_FLAG_EXTENDED_DATA    BIT(1) /* EC returns 256 data bytes */
+#define WILCO_EC_FLAG_RAW_REQUEST      BIT(2) /* Do not trim request data */
+#define WILCO_EC_FLAG_RAW_RESPONSE     BIT(3) /* Do not trim response data */
+#define WILCO_EC_FLAG_RAW              (WILCO_EC_FLAG_RAW_REQUEST | \
+                                        WILCO_EC_FLAG_RAW_RESPONSE)
+
+/* Normal commands have a maximum 32 bytes of data */
+#define EC_MAILBOX_DATA_SIZE           32
+/* Extended commands have 256 bytes of response data */
+#define EC_MAILBOX_DATA_SIZE_EXTENDED  256
+
+/**
+ * struct wilco_ec_device - Wilco Embedded Controller handle.
+ * @dev: Device handle.
+ * @mailbox_lock: Mutex to ensure one mailbox command at a time.
+ * @io_command: I/O port for mailbox command.  Provided by ACPI.
+ * @io_data: I/O port for mailbox data.  Provided by ACPI.
+ * @io_packet: I/O port for mailbox packet data.  Provided by ACPI.
+ * @data_buffer: Buffer used for EC communication.  The same buffer
+ *               is used to hold the request and the response.
+ * @data_size: Size of the data buffer used for EC communication.
+ */
+struct wilco_ec_device {
+       struct device *dev;
+       struct mutex mailbox_lock;
+       struct resource *io_command;
+       struct resource *io_data;
+       struct resource *io_packet;
+       void *data_buffer;
+       size_t data_size;
+};
+
+/**
+ * struct wilco_ec_request - Mailbox request message format.
+ * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
+ * @checksum: Sum of all bytes must be 0.
+ * @mailbox_id: Mailbox identifier, specifies the command set.
+ * @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
+ * @reserved: Set to zero.
+ * @data_size: Length of request, data + last 2 bytes of the header.
+ * @command: Mailbox command code, unique for each mailbox_id set.
+ * @reserved_raw: Set to zero for most commands, but is used by
+ *                some command types and for raw commands.
+ */
+struct wilco_ec_request {
+       u8 struct_version;
+       u8 checksum;
+       u16 mailbox_id;
+       u8 mailbox_version;
+       u8 reserved;
+       u16 data_size;
+       u8 command;
+       u8 reserved_raw;
+} __packed;
+
+/**
+ * struct wilco_ec_response - Mailbox response message format.
+ * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
+ * @checksum: Sum of all bytes must be 0.
+ * @result: Result code from the EC.  Non-zero indicates an error.
+ * @data_size: Length of the response data buffer.
+ * @reserved: Set to zero.
+ * @mbox0: EC returned data at offset 0 is unused (always 0) so this byte
+ *         is treated as part of the header instead of the data.
+ * @data: Response data buffer.  Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
+ */
+struct wilco_ec_response {
+       u8 struct_version;
+       u8 checksum;
+       u16 result;
+       u16 data_size;
+       u8 reserved[2];
+       u8 mbox0;
+       u8 data[0];
+} __packed;
+
+/**
+ * enum wilco_ec_msg_type - Message type to select a set of command codes.
+ * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
+ * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
+ * @WILCO_EC_MSG_TELEMETRY_SHORT: 32 bytes of telemetry data provided by the 
EC.
+ * @WILCO_EC_MSG_TELEMETRY_LONG: 256 bytes of telemetry data provided by the 
EC.
+ */
+enum wilco_ec_msg_type {
+       WILCO_EC_MSG_LEGACY = 0x00f0,
+       WILCO_EC_MSG_PROPERTY = 0x00f2,
+       WILCO_EC_MSG_TELEMETRY_SHORT = 0x00f5,
+       WILCO_EC_MSG_TELEMETRY_LONG = 0x00f6,
+};
+
+/**
+ * struct wilco_ec_message - Request and response message.
+ * @type: Mailbox message type.
+ * @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
+ * @command: Mailbox command code.
+ * @result: Result code from the EC.  Non-zero indicates an error.
+ * @request_size: Number of bytes to send to the EC.
+ * @request_data: Buffer containing the request data.
+ * @response_size: Number of bytes expected from the EC.
+ *                 This is 32 by default and 256 if the flag
+ *                 is set for %WILCO_EC_FLAG_EXTENDED_DATA
+ * @response_data: Buffer containing the response data, should be
+ *                 response_size bytes and allocated by caller.
+ */
+struct wilco_ec_message {
+       enum wilco_ec_msg_type type;
+       u8 flags;
+       u8 command;
+       u8 result;
+       size_t request_size;
+       void *request_data;
+       size_t response_size;
+       void *response_data;
+};
+
+/**
+ * wilco_ec_mailbox() - Send request to the EC and receive the response.
+ * @ec: Wilco EC device.
+ * @msg: Wilco EC message.
+ *
+ * Return: Number of bytes received or negative error code on failure.
+ */
+int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
+
+#endif /* WILCO_EC_H */
-- 
2.20.1.791.gb4d0f1c61a-goog

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